Formation of ice on windows positioned on a vehicle obscures visibility as well as decreases effectiveness of wipers installed proximate to the windows positioned on the vehicle. A heat source or a defrosting device is generally used in such situations to remove snow and ice. Devices of this type increase the temperature of the window thereby preventing formation of ice and melting any ice already formed. However, the ice may refreeze as an ambient-facing surface of the window cools, for example; after all defrosting devices and heat sources are deactivated.
In a known wiping system, a control system for operating an electrically actuated device in response to presence of moisture on a window is provided. A moisture sensor having a plurality of spaced apart, exposed conductive strips detects the presence of moisture on an ambient-facing surface of the window. The control system connected to the moisture sensor can activate the window wiper in response to detection of moisture. However, in such systems there is a delay in detection and the ice may have refrozen, result in freezing of the window wiper.
In another wiping system, two additional sensors are provided that enable melting of the ice immediately after the vehicle is shut-down. An ignition sensor detects start and shut-down of the vehicle and a window temperature sensor senses temperature of the window. A controller coupled to each of the sensors activates the window wiper assembly depending upon the signals received from the sensors. However, the wiping system cannot predict refreezability of meltable snow and enable the window wiper assembly well in advance before the meltable snow starts to melt leading to the same problem of delay in detection and causing the freezing of the window wiper.
In light of the above discussion, there is a need for a wiping system that overcomes one or more drawbacks associated with the prior art.